1. Field of the Invention
The present invention relates to a broadcast processing method for performing broadcast from one node to a plurality of other nodes in a network system in which a plurality of nodes are connected via a network, and to the network system, and more particularly to a broadcast processing method for a network system for efficiently broadcasting using a plurality of network adapters in each node, and to the network system.
2. Description of the Related Art
As higher speeds for computer systems are demanded, a network type computer system, in which a plurality of nodes including computers is installed and is connected via the network, has been proposed. In the field of parallel computers, for example, data is computed in parallel by a plurality of nodes, and the processed data is exchanged via the network. Such parallel computers have several hundred-several thousand nodes if the scale becomes large.
In such a network system, the data of one node is transferred to a plurality of other nodes via the network. This is called “broadcast processing”. In this broadcast processing, mass data is sometimes transferred, and decreasing the transfer processing time is desired.
FIG. 11 and FIG. 12 are diagrams depicting a broadcast processing of a first conventional network system. As FIG. 11 shows, a plurality of (four in this case) of nodes 100, 101, 102 and 103 are connected via a network, which is not illustrated. Each of these nodes 100, 101, 102 and 103 has a plurality (three in this case) of network adapters 110A, 110B and 110C to enable parallel transfers.
If one node 100 broadcasts data to the other three nodes 101, 102 and 103 in this configuration, all transfer data is transferred from the network adapters 110A, 110B and 110C of the node 100 to the corresponding network adapters 110A, 110B and 110C of each node 101, 102 and 103 in parallel.
For example, as shown in FIG. 12, if the transfer data of 12 blocks D0 to D11 is transferred from the node 100 to the other three nodes 101, 102 and 103, the 12 blocks D0 to D11 are transferred from the network adapter 110A of the node 100 to the network adapter 110A of the node 101, from the network adapter 110B of the node 100 to the network adapter 110B of the node 102, and from the network adapter 110C of the node 100 to the network adapter 110C of the node 103 respectively.
In this way, according to the first prior art, the time required for broadcast processing is decreased by parallel transfer for each node 100, 101, 102 and 103 to have a plurality of transfer channels (network adapters).
FIG. 13 and FIG. 14 are diagrams depicting a broadcast processing of a second conventional network system. According to this method, when data is broadcasted among each node having a plurality of network adapters, just like FIG. 11, a transmission source node 100 divides the transmission data and transfers it from each network adapter.
In other words, as FIG. 13 and FIG. 14 show, the transmission source node 100 divides the transmission data blocks D0 to D11 into three, and the divided blocks are transferred from the three network adapters 110A, 110B and 110C of the node 100 to the network adapters 110A, 110B and 110C of the node 102, as shown in sign (1).
Since there are two nodes which hold the transmission data, the transmission node 100 transfers each of the data blocks divided into three from the three network adapters 110A, 110B and 110C of the node 100 to the network adapters 110A, 110B and 110C of the node 101, as shown in sign (2). At the same time, the node 102 transfers each of the divided data blocks received from the node 100 from the three network adapters 110A, 110B and 110C of the node 102 to the network adapters 110A, 110B and 110C of the node 104, as shown in sign (3).
If the transfer data length is long, the broadcast processing time is normally in proportion to the data volume that propagates the network, so a processing time to transfer 12 blocks is required for the first prior art, but in the second prior art, the data blocks are divided into three and transferred twice, so a transfer time for four blocks is required twice, in other words, a processing time becomes only 8/12=⅔ of the processing time of the first prior art (e.g. Japanese Patent Application Laid-Open No. H7-244648).
In the case of the second prior art, however, a copy of the transfer data of the broadcast source node 100 is held by the node 102 in the first transfer, and a full transfer data is transferred from two nodes at the transfer source and copy destination, that is nodes 100 and 102, to two nodes 101 and 103 in the second transfer for broadcasting the data.
Therefore in the second prior art, the broadcast processing time is limited, and in particular when the data transfer length is long, it is difficult to decrease the broadcast processing time.